1. Field of the Invention
The present invention relates to a storage device and a host apparatus (electronic apparatus) using a storage device. In particular, the present invention relates to a storage device such as a non-volatile semiconductor storage device and a memory card using it. In addition, the present invention relates to an electronic apparatus such as a recording apparatus; for example, a digital still camera and a digital video camera having the storage device built in. For example, a storage device such as a universal serial bus (USB) flash and electronic apparatus such as a personal computer (PC) and a personal digital assistant (PDA) are included in the category of the present invention.
2. Description of the Related Art
In recent years, a memory card having a built-in non-volatile semiconductor memory has come into widespread use as a storage device storing various kind of digital information such as image data and music data. The data of the non-volatile semiconductor memory is not at risk of being lost even if power is turned off, and is rewritable. A NAND Flash™ memory is frequently used as a non-volatile memory (for example, see JPN. PAT. APPLN. KOKAI Publication No. 2003-30993).
Recently, the memory capacity of the flash memory has increased with advances in the technique of manufacturing semiconductors.
For example, a storage device such as memory card having a built-in flash memory is used via a host apparatus. In this case, the host apparatus directly controls the flash memory built into the storage device in the conventional case. Thus, the host apparatus grasps program time of the flash memory, and can predict memory performance and storable time to some degree from the program time.
However, it is often now the case that the storage device has a built-in controller; for this reason, the control has become complicated. As a result, it is impossible to predict the memory performance using a simple calculation. The transfer rate parameter of a bus connecting the host apparatus and the storage device is defined. However, this is not the real rate when the host apparatus writes data to the storage device. For this reason, the transfer rate does not function as a means for identifying the performance.
In order to predict the performance of a storage device including a NAND Flash™ memory, calculation is required in combination with a block processing method by the host apparatus. For this reason, it is difficult to determine the performance using only the storage device.
Accordingly, it is desired to provide an electronic apparatus which can simply predict storage device performance to some degree even if a large-capacity storage device is controlled via a controller, a method of predicting the performance, and a storage device.